DIY Kits - Assembling and Mounting

Time to finish your Gecho!

If you received some version of the DIY kit, there is a few things to do, before you can enjoy the music.

Soldering THT components

In the parcel you should have received three black 3.5mm Jack connectors, those are for headphones outputs and pickups input. There is also a magnetic sensor (has 3 leads, looks like a transistor), one or two battery holders (3xAAA or 2xAA+1xAA) and two bronze-finish self tapping screws for mounting the board in the enclosure.

If you got 3xAAA battery holder, there is also a metallic contact included - because this holder does not have 3 leads out, and you might want to take 3V voltage from between second and third battery, and connect it to the "BAT3V" pad.

Position of THT elements you need to add, plus wiring for batteries, looks like this:

Be sure that the Jack connectors are pressed against the board well so they sit on it tightly and without a gap, otherwise it won't look good.

Magnetic sensor pads are close together. Make sure to either bend their ends, so there is no chance of short circuit from the middle lead to other two lead's pads, or use some insulating material - e.g. heat shrink tubes. Also, it is good to shorten them by approximately 5mm first. When bending, make sure the direction is away from "front" side of the element (the one where the marking text is).

MIDI Circuitry (optional)

If you also ordered loose SMD components for adding the MIDI by yourself, please follow this layout. You need to assemble 6 resistors (of 0603 size), one 6-leaded opto-coupler and one diode (please note the orientation). The connectors can then be mounted for example like explained here.

Important: apart from elements, do not forget about a soldering bridge, in the schematics denoted by "IN(-) sel", it is used to select which opto-coupler's lead the negative MIDI IN signal goes to (because various opto-couplers are supported). In our case, we need to connect middle and lower pads of this soldering bridge.

The rest - voltages and Rx/Tx signals are shown only for reference and test/debug purposes, and are wired internally in the PCB, no need to connect anything there.

After soldering everything, you should get something like this. Note how thanks to shortening of the magnetic sensor's leads, it got positioned roughly in the centre of the board. It does not need to be exactly in the centre, plus minus few millimetres don't really matter. And if you forgot to shorten them, it will work fine (it's not worth reworking and risking damaging something).

Expansion Pads

Should you want to wander further within your DIY efforts, here is a quick description of solderable pads that let you use various interfaces and signals from MCU. Most of them are occupied by LEDs but those are not really in the way, apart from acting like a pull-down or pull-up resistors, so please take this into consideration. First two rows of LEDs (red and orange) are driven by active high logic, therefore wired in a common-cathode way, the rest (blue and white) are driven with active low, so wired as a common-anode.

For easy reference, colour of pads in following picture equals colour of LEDs, and the four CV pads (wired to IR distance sensors, but possible to safely override with external voltage in 0 to 3.3V range) are shown in green.

Got our box as well? Here you can get some ideas about how to put everything together.


Hi Mario,

I received the Gecko last week. Thanks.

I soldered the three jack connectors without any problem.
I have a problem with the magnetic sensor.
Is it mounted on top side ?

I see well where to mount the sensor in the three holes of the board.

Can you send a photo to illustrate the position of the sensor ?

Thank you for your help.


Hi Gérard,

Glad to hear it arrived - and hope you like it! :)

Good idea, one picture is worth a thousand words - I've added a photo so there is no doubt about the placement and orientation.